The present invention relates in general to fork lift trucks and, more particularly, to the mounting of a multi-function control handle which is generally horizontally oriented so that the handle can be moved in any direction with approximately the same force, at least as perceived by an operator of a truck including the invention.
Control handles for several types of fork lift trucks are oriented vertically; however, on some trucks, for example rider reach trucks, the control handles are oriented generally horizontally. Typically, a horizontally orientated multi-function control handle includes an elongated body which is moved forward and backward to operate sensors and switches which control the direction and speed of travel of the truck, and upward and downward to operate sensors to control raising and lowering of forks of the truck. Additional control sensors and switches may be located at the end of the handle to control auxiliary functions of the truck, such as to control fork tilt, reach, and side shift. A horn button and selector switch may also be located at the end of the control handle. These auxiliary switches are usually manipulated by the operator's thumb and forefinger.
For durability and long life in the normally harsh operating environment in which fork lift trucks operate, the control handles must be of a sturdy construction. Such sturdy construction, together with the auxiliary control mechanisms, leads to a handle which has substantial weight. When the weight of the operator's hand is added to the weight of the control handle, conventionally supported control handles tend to be relatively easy to move downwardly due to the force of gravity. Prior art control handles include a variety of support arrangements to return the handles to neutral or center positions, oftentimes taking the form of spring biasing the handles so that when the handles are moved away from neutral positions springs are biased to return the handles to the center positions.
For control handles which are generally horizontally mounted, the conventional approach has been to increase the forces applied by springs biasing the handles to neutral positions. Unfortunately, such increased spring forces make it harder to move the handles upwardly as well as from side to side thus reducing the ease of moving the control handles and thereby reducing the ease of controlling trucks including the handles.
It is apparent that there is a need for an improved horizontally oriented control handle which can be moved in any direction with approximately the same force so that an operator of a truck including the handle can more easily and accurately control the handle and hence the truck including the handle.